seismograph

Everyday

A machine that measures and records how much the ground shakes during an earthquake. tree →

In the lessons

In geography and science lessons seismographs show earthquakes as zigzag lines on paper or a screen; bigger zigzags mean stronger shaking. Scientists use them to find where an earthquake happened and how strong it was. Phrases: «seismograph reading», «recorded on a seismograph».

Examples

• The seismograph drew big zigzag lines during the earthquake. tree →
• Scientists in New Zealand watch seismographs day and night. tree →
• A seismograph can detect earthquakes on the other side of the world. tree →
• We made a model seismograph with a pen and a moving strip of paper. tree →
• The seismograph showed small shakes before the volcano erupted. tree →
• Seismograph records help warn people about tsunamis. tree →

Note

Pronounced «SIZE-muh-graf». «Seismo-» means earthquake, «-graph» means writing or drawing. The record is a «seismogram»; the science is «seismology». Earthquake strength is given on the moment magnitude scale; each step up means much more energy (about 32 times more).